The present invention relates to flow meters. Known flow meters have drawbacks which make them unsuitable for measuring microflows, particularly under certain conditions, notably those which are encountered when measuring the pulsed flow of fuel consumed by an automobile vehicle. Vane flow meters are only suitable for relatively large flows and are very complicated when they are intended for measuring instantaneous flows. The electronics of thermometric bridge flow meters are elaborate, therefore costly and are sensitive to the thermal parameters of fluids, to ambient temperature, and to inclination. Float flow meters have the drawback that they do not supply a reading in the form of an electrical magnitude. Vortex flow meters are sensitive to dynamic variations and unsuitable for low flows.